The purpose of this research is to take advantage of an unusual opportunity to observe changes in prescribing patterns of minor tranquilizers when change in forced upon the prescriber--in this case by the imposition of a state Medicaid formulary. Data will be gathered from a stratified random sample of Mississippi pharmacies via audit of vendor claim forms. Claim forms for similar six-month periods before and after establishment of formulary restrictions will be analyzed to determine, to the extent possible, the nature and suitability or drugs chosen by physicians as substitutes for minor tranquilizers no longer paid for by the Medicaid program. The hypothesis to be tested is that the change in the formulary has resulted in "trading up" to major tranquilizers on behalf of the Medicaid patient.